Preheat oven to 400 degrees.

Peel the apples and sweet potatoes. Chop the potatoes into bite-sized chunks and thinly slice the apples.

Transfer the apples and potatoes to a large bowl. Pour the 1/2 cup maple syrup over top. Sprinkle cinnamon, nutmeg and salt into the bowl. Toss well to thoroughly combine.

Coat a 8x11 baking dish with cooking spray. Transfer the apple mixture into the dish.

Cover with foil, and bake for 40 minutes. (The apples will cook faster than the sweet potatoes, but the foil prevents them from burning at all.)

Remove foil and drizzle the remaining maple syrup on top. Bake until the potatoes are tender, another 5-10 minutes.

Serve while it's still hot!